CVCs are used primarily to gain access to the venous system of a patient for administering intravenous therapy, such as drugs, chemotherapy, and total parenteral nutrition. They can also be used to provide access to the patient for blood sampling and central venous pressure monitoring. The most common technique used by a clinician to gain access to the central venous system of the patient with a CVC is a landmark guided technique known as the Seldinger technique, which is illustrated in FIG. 1. This technique involves the clinician first inserting a needle 2 through the patient's skin 4 at a peripheral location and into a vein to form a venotomy (FIG. 1a). A blunt guidewire 6 is then passed through the channel of the needle 2 (FIG. 1b), and then the needle 2 is removed (FIG. 1c). Next, a dilating device 8 is passed over the guidewire 6 to slightly enlarge the tract originally produced by the needle 2 (FIG. 1d), and then make way for a catheter 10, which is then passed over the guidewire 6 (FIG. 1e). Finally, the guidewire 6 is removed from the patient leaving the catheter 10 in position (FIG. 1f). All channels in the catheter are then aspirated and flushed with saline to ensure that they are all positioned inside the vein.
However, many problems have presented themselves in terms of how effectively a CVC can be deployed in and along a patient's vein using the above multi-step technique, especially with the use of real-time ultrasound imaging, and how this might impact, not only on the comfort of the patient, but also any medical risks that could be presented to the patient as a result. For example, such landmark guided techniques may be more commonly associated with accidental injury to adjacent structures such as the carotid artery, with serious consequences such as stroke or aneurysm formation, thereby increasing morbidity in patients. Hence, the National Institute of Clinical Excellence has provided some assistance concerning the use of ultrasound in these techniques in order to minimize such mishaps. However, a purpose-built central venous catheter for use under ultrasound guidance does not currently exist, and so catheters usually intended to be used in landmark guided techniques, e.g. Seldinger technique, are still being used. Other problems associated with deployment include how to keep the catheter or a surrounding region sufficiently sterile using the Seldinger technique referred to above, especially with the use of ultrasound.